Nervous Tissue

Neural or nervous tissue is a special tissue with specific functions. Nervous tissues are an integral part of the nervous system, both the central nervous system and the peripheral nervous system. We can find these tissues in the brain, spinal cord, and nerves. It is responsible for controlling and coordinating many bodily functions. 

It stimulates muscle contraction, creates environmental awareness, and plays a major role in emotion, memory, and thinking. For all these functions to work, neural tissue cells must be able to communicate with other electrical nerve impulses. 

Nerve cells that produce and process impulses are called neurons. These cells consist of three main components: dendrites, body cells, and a single axon. 

The main part of the cell, the part that performs normal functions, is the cell’s body. Dendrites are outgrowths, or processes, of the cytoplasm that carry impulses throughout the cell body. An extension called axons moves nerves away from the cell body.

Nervous tissue consists of cells that do not transmit impulses but instead support the functions of neurons. These are glial cells, which are collectively called neuroglia. These helper cells bind neurons together. Some are phagocytic and protect against bacterial invasion, while others provide nutrients by binding to neurons in blood vessels.

Classification of Nervous Tissues

We can classify nervous tissues based on their location.

In the central nervous system:

The grey matter consists of cellular bodies, dendrites, implanted axons, and protoplasmic astrocytes (astrocyte subtype). They also contain satellite oligodendrocyte (non-myelinating oligodendrocyte subtype), microglia, and a few myelinated axons.

The white matter has myelinated axons, fibrous astrocytes, myelinated oligodendrocytes, and microglia.

In the peripheral nervous system:

Ganglion tissue comprises stem cells, dendrites, and glial satellite cells. The nerves are composed of myelinated and unmyelinated axons, Schwann cells surrounded by connective tissue.

Components of the Nervous Tissue

Neural tissues consist mainly of neurons and neuroglia. Neurons or nerve cells are very special cells that can produce and drive nerve impulses. There are supportive neuroglial cells that help remove waste, give physical support and provide electrical implants.

Neuron

A neuron is a basic unit of the nervous system with a cell body, dendrites, axons, and axon terminals. Dendrites and axons are thin processes. 

The neuron cell body consists of the nucleus, endoplasmic reticulum, Golgi apparatus, etc. It performs the basic health processes of the neuron.

Dendrites are a type of motor neuron that have a large surface area. Their length is also less. Dendrites have a large surface area to receive signals from other neurons. The incoming message is transmitted to the cell body by the dendrites. Therefore, we call them receiving input circuits.

The cell’s body has a cone-shaped shape, from which an axon emerges. The axons are very long and narrow. They are like a fence and can climb up to a few metres. This axon design facilitates reliable and rapid transmission of information. 

The primary function of the axon is to process signals. This cell is highly responsible for producing and transmitting impulses away from the body.

The axon carries nerve impulses from the body of a cell to other neurons. The axon may also have multiple maintenance branches. Axon terminals located at the ends of axons connect to other neurons.

Classification of Neurons

Neurons are both functional and structural:

Classification based on function:

Sensory neurons (afferent): Transfer sensory information through a potential nerve (nerve impulse) from the PNS to the CNS

Motor neurons (efferent): Transfer the action force from the CNS to the right maker (muscles, glands)

Interneurons: Cells that form connections between neurons and their processes. They are limited to a specific area of ​​the brain or spinal cord.

Classification based on structure:

Multipolar neurons: Have three or more processes coming out of the soma (cell body). They are a major type of neuron in the CNS and include interneurons and motor neurons.

Bipolar neurons: Sensory neurons with two processes coming out of the soma, one dendrite and one axon.

Pseudo unipolar neurons: Sensory neurons have a single process that divides into two branches, forming an axon and a dendrite.

Unipolar brush cells: Exciting glutamatergic interneurons have a single short dendrite that passes through a tuft similar to a brush of dendrites. These are present in the granular layer of the cerebellum.

Functions of the Nervous Tissue

The function of the nervous system is to make the communication network of the nervous system by transmitting electrical signals to all tissues. 

In the CNS, grey matter, which contains synapses, is essential for processing information. The white matter, which contains myelinated axons, connects and simplifies nerve pressure between the grey areas in the CNS.  

In PNS, ganglion tissue, consisting of cell bodies and dendrites, contains the transmission points of nerve tissue impulses. Nerve tissue, which contains many myelinated axons, carries the potential for nerve endings.

Conclusion

 Nervous tissue, also called neural tissue, is a major component of the nervous system.The nervous tissue is a type of soft tissue that helps transmit electrical signals all over the body. It consists of the brain, spinal cord, and nerves, which are the critical parts of nervous tissue. Nervous tissue is found all over the body except in nails and hair. It helps in the simulations and electric impulse transportation.The main part of the cell, the part that performs normal functions, is the cell’s body. Dendrites are outgrowths, or processes, of the cytoplasm that carry impulses throughout the cell body. An extension called axons moves nerves away from the cell body.